Steam-boiler



(No Model) 2 Sheets-Sheet 1. v

J'. JOHNSON.

STEAM BOILER.

No. 381,791. Patented Apr. 24, 1888.

facture of the boilers.

UNITED STATES PATENT OFFICE.

JONATHAN JOHNSON, OF LOWELL, MASSACHUSETTS.

STEAM- BOILER.

SPECIPICATION forming part of Letters Patent No.381fi91, dated April 24,1888.

Application filed September 19, 1887. Serial No. 250,086. (No model.)

.To all whom it may concern:

Be it known that I, JONATHAN J oHNsoN, a citizen of the United States,residing at Lowell, in the county of Middlesex and State ofMassachusetts, have invented certain new and useful Improvements inSteam-Boilers; and I do declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same, referencebeing had'to the accompanying drawings, and to the letters and figuresof reference marked thereon, which form a part of this specification.

This invention relates to improvements in that class of steam andhot-water boilers especially designed for heating purposes, althoughthey may be used as power-generators, if desired, and is an improvementon the boilers for which Letters Patent have been granted to me, saidpatents being No. 274., 785, dated March 27, 1883, and N o. 338,670,dated March 23, 1886, the object being to so connect a we.- ter-heatingchamber surrounding the grate and forming the receptacle for fuel withthe ordinary tubular horizontal boiler, by means of suitable pipes, asto insure a perfect circulation of the water through both heatingchamberand boiler.

A further object is to improve the general construction and arrangementof the several parts, so as to produce a boiler which shall be durable,safe, and give out the maximum effect to be obtained from the combustionof fuel in a steam-generating apparatus.

To "carry out this invention I provide a heater formed as a chamberedring or annulus. If a circular grate be used, or if the grate berectangular, the heatingchamber surrounding it will have the samegeneral .form. This heater I prefer to make of cast-iron in a singlepiece, cored out to form the internal chamber, although, if desired, itmay be made of boiler-plate iron, but at a considerable increase ofexpense, and as the cast-iron heat-' ing-chamber has proved perfectlyreliable, as well as more durable, I prefer it in the manu- Thisheating'chamber may be connected with the boiler above itby a series oftubes, the lower ends of which are inserted in the fire-box orheating-chamber near its top. They then pass through the combustionchamber under the boiler and en ter said boiler at the rear near thewater-line. Another tubular connection is formed between the bottom ofthe horizontal portion of the boiler near its rear end and the lowerrear side of the heating-chamber. The pipe forming this connection iscarried down to a position where it will not be directly affected byheat, and is inclosed by masonry or outside pipes with packing'toprotect it and keep it comparatively cooler than the water in theboiler, so that there may be an uninterrupted return-flow through itfrom the horizontal part of the boiler to the heating-chamber to supplythe deficiency of water in the latter caused by the upward flow throughthe side or horizontal pipes when the fuel upon the grate is in anactive state of combustion, thus insuring a thorough circulation throughthe boiler and preventing the deposit of scale or dangerous increase ofheat at any point.

In the accompanying drawings, Figure l is a vertical longitudinalsection through the boiler, fire-box, and casing. Fig. 2 is a horizontalsection on the line a: m, Fig. 1. Fig. 3 is a rear elevation showing theposition of the pipes which connect the upper part of the heater withthe horizontal boiler. Fig. 4 is a vertical section on a line in rear ofthe heater, illustrating the relative arrangement of the grate, heater,connecting-pipes, and horizontal boiler.

In the several figures, A represents the outer casing which surroundsthe boiler, and which may be of metal or brick, as best suited to thesize and location of the apparatus.

B is the horizontal boiler, provided with the series of tubes at a,through which the products of combustion pass on their way to thechimney, said tubes passing through the water in the boiler, the uppersurface of which is carried above the top of the tubes.

0 represents the water-heating chamber or fire-box placed beneath thehorizontal boiler B, and connected therewith by means of the tubes b andc, the tubes 1) being connected at their lower ends to the upper part ofthe heating-chamber C by elbows b, and to the tubular boiler by the armsI), said arms projecting vertically at right angles from the horizontalportion of the tubes, and being of sufficient length to connect with theboiler B near its r i r water-line. These tubes, passing through thecombustion-chamber in rear of the fire-box,are in a position to take upheat quickly and impart it to the contents of the boiler by the steadyflow through them of water passing from the fire-box to the boiler.Additional pipes, as e e, may be placed, ifdesired, at the sides of theboiler,passing out from the fire-box through the casing at their lowerends, and returning through the same to the boiler at their upper ends.

Connected to the outside and rear of the heatingchamber, near itsbottom,by any suitable connect-ion, is the circulatingpipe c,whicl1 maybe carried to one side by bending or by suitable elbows, so as to removeit from the direct action of the fire, and provided with a verticalextension, 0, by which it is connected with the lower part of thehorizontal boiler. Through this pipe the water descends from thehorizontal boiler B to the lower part of the boiler or chamberedfire-box G to supply the place of that which ascends through the pipes band e, and should therefore be protected from the heat to obviate anytendency to rise on the part of its contents.

If desired, the water-supply pipe for replenishing any loss of water inthe boiler may be connected with the pipe 0, and will be found tooperate in a perfect manner,as it introduces the cold water at the bestpoint to enableit to assist in the circulation,as well as receive heatfrom the fire through the walls of the heatingchamber.

(1 represents a steam exit pipe.

The grate E, as shown in the drawings, is

placed at the bottom of the heating-chamber O. The latter thereforeserves as a fire pot or box to receive the fuel, its upper edge being sofar beneath the boiler as to leave room beneath them for theintroduction of fuel through the fire-door f. It also acts as abridge-wall between the fuel and combustion chamber D at the rear ofsaid heating-chamber beneath the tubular boiler, from which the productsof combustion pass through the tubes and into the chimney after havingimparted to the watcr in the boiler nearly all the available heatproduced by the combustion of the fuel.

This boiler will be found very efficient and durable as a steamgeneratoror for hot-water circulation where anthracite coals are used for fuel,although other fuels may be used therein without detriment, as the tubesare easily cleaned, when their heating qualities deterio' rate owing toan accumulation of soot,by pass ing a brush through them.

I am aware that it is not new to employ a fuel-receptacle constructed toact as a heater detached from but in connection with a horizontaltubular boiler, and do not, therefore, broadly claim such aconstruction.

Having thus described my invention, Iclaim as new, and desire to secureby Letters Patent, the following:

1. As an improvement in steam-generators, the tubular horizontal boiler,in combination with the detached heatingchamber formingafuel-receptacle, and the series of circulatingpipes b, passing throughthe combustion-chamber andconneeting the top of said heater with therear of the boiler, for the purpose of conveying water from the heaterto the boiler and assist in maintaining a circulation between them, asset forth.

2. As an improvement in steamgencrators, the combination of the outercasing, the horizontal tubular boiler, the detached heater, thecirculating-pipes 1), connecting the top of the heater with the rear ofthe boiler, and the pipe 0, connecting the bottom of the boiler with thebottom of the heater, said pipebeing deflected to one side, so as to beprotected from the direct action of the heat, all as shown anddescribed.

In testimony whereof I affix my signature in presence of two witnesses.

JONATHAN JOHNSON.

\Vitnesses:

GEO. H. Sruvnns, SAMUEL B. WYMAN.

